Geological Relations of the South of Ireland. 381 



2. " Notes on the Strata exposed in laying out the Oxford 

 Sewage-Farm at Sandford-on-Thames." By E. S. Cobbold, Esq., 

 F.G.S., Assoc.M.Inst.C.E. 



The beds noticed in this paper belong to the Kimmeridge Clay 

 and the upper and middle part of the Oxford Oolite. They were 

 exposed (over an area of about 1^ mile by 1 mile) in making deep 

 trenches for a sewage-farm, about 4 miles south of Oxford. The 

 author described variations in the Coralline Oolite and Coral Bag, 

 which become, in places, a marl without corals. The Calcareous 

 Grit also is variable in character. On either side of this tract, at 

 Headington and Cumnor, are coralliferous strata. Thus it appears 

 to indicate a gap in the reef. The clay may indicate the proximity 

 of some river, which thus caused an interruption. The author gave 

 reasons for thinking that it came from the S.E., and suggested 

 that it may have descended from the Palaeozoic ridge beneath 

 London. The paper also included some notes on the Eimmeridge 

 Clay and a peat deposit. 



3. "A Review and Description of the various Species of British 

 Upper-Silurian Fenestellidge." By G. W. Shrubsole, Esq., E.G.S. 



In this paper the author passed in review the forms of Fenes- 

 tellidge which have been described from British Upper Silurian 

 rocks. These amount to nine in all — six described by Lonsdale, two 

 by M'Coy, and one by Portlock. From the imperfect condition of 

 the specimens at the command of these authors, and especially from 

 their characters being masked by an incrusting growth of corals &c. 

 and by subsequent matting, it is inmost cases impossible to identify 

 them, only one of the nine species, namely F. rigidula, M'Coy, 

 being recognizable. The author discusses the peculiarities of these 

 supposed species, of which he adopts only F. rigidula ; and describes 

 the other forms known to him under the following new names : — - 

 Fenestella reteporata, F. lineata, and F. intermedia. The author 

 further discussed the relations of the Silurian Fenestellidse to those 

 of the Carboniferous and to other organisms. 



March 10, 1880.— Eobert Etheridge, Esq., F.R.S., 

 President, in the Chair. 



The following communication was read : — 



1. " On the Geological Relations of the Rocks of the South of 

 Ireland to those of North Devon and other British and Continental 

 Districts." By Professor Edward Hull, M.A., LL.D., F.R.S., F.G.S., 

 Director of the Geological Survey of Ireland. 



In this paper the author, after referring to his previous paper on 

 the geological age of the Glengariif beds (Quart. Journ. Geol. Soc. 

 vol. xxxv. p. 699), in which he showed that between them and the 

 succeeding Old Red Sandstone in the south of Ireland there existed 

 a very great hiatus, proceeded to compare the sections of the rocks 

 of the south of Ireland with those of North Devon, and to show 

 that the hiatus in question is represented in the latter locality by 

 the whole of the Middle and Lower Devonian rocks. He then 

 discussed the relations of the Devonshire rocks to those occurring 

 north of the Severn, in Scotland, and in Belgium ; and from this 



